Structural, magnetic, and dielectric properties of Ti⁴⁺−M²⁺ co-doped BaFe₁₁Ti_0.5M_0.5O₁₉ hexaferrites (M=Co²⁺,Ni²⁺,Zn²⁺)

Pure BaFe₁₂O₁₉ and Ti⁴⁺−M²⁺ co-doped BaFe₁₁Ti_0.5M_0.5O₁₉ (M = Co²⁺, Ni²⁺, Zn²⁺) hexaferrites were synthesized by a co-precipitation method. X-ray diffraction (XRD) patterns confirmed the formation of single-phase M-type hexagonal structure with P6₃/mmc space group. The structural analysis indicated that Ti−Ni and Ti−Zn co-doped samples enhanced the values of lattice parameters (a,c) and cell volume (V) in comparison to Ti−Co sample. Scanning electron microscopy (SEM) was used to investigate the effects of co-doping on the microstructure, whereas the elemental composition of prepared samples was verified by the energy dispersive X-ray spectroscopy (EDX). Impedance spectroscopy measurements revealed a significant variation in the dielectric properties of Ti⁴⁺−M²⁺ co-doped samples which can be associated with the values of grain and grain boundary resistance. The magnetic hysteresis loops exhibited a ferrimagnetic behavior at room temperature. However, Ti−Ni and Ti−Zn co-doped samples showed considerably high values of magnetization along with reduced coercivity. These variations in the obtained results are elucidated based on the site preferences of co-doped ions, mobility of charge carriers, and microstructure. Here, our findings of high dielectric permittivity, diminished dielectric tangent loss, better conduction, moderate magnetization and reduced coercivity for the Ti−Ni co-doped BaFe₁₁Ti_0.5Ni_0.5O₁₉ sample make this composition favorable for electromagnetic absorbing applications.